# 98.6 Trades Metabolic Cost for Fungal Protection

A mathematical model finds that a temperature of about 98.6 Fahrenheit is high enough to ward off the majority of fungal infections, but still low enough to only require a manageable level of food intake. Steve Mirsky reports

### Listen to this Podcast

As a bitter winter storm rages on the East Coast, it’s hard to knock being warm-blooded. But what about the metabolic cost of maintaining a high body temperature? Well, a new study finds that we and many other mammals keep up such a torrid temp because it’s a Goldilocks situation—98.6 is just right.

Albert Einstein College of Medicine researchers previously showed that every one degree Celsius rise in body temperature wards off about 6 percent more fungal species. So tens of thousands of fungi can infect reptiles and amphibians, but we can only be invaded by a few hundred fungi.

In the new work, the researchers created a mathematical model that weighed the fungal protection benefits versus the metabolic cost of high body temperature. And the optimal temperature was 98.1, quite close to what evolution figured out. The research was published in the open-access journal mBio. [Aviv Bergman and Arturo Casadevall, "Mammalian Endothermy Optimally Restricts Fungi and Metabolic Costs"]

Too low a temperature and we’re far more susceptible to fungal infections. Too high a temperature and we’d spend all our time taking in fuel to burn. So 98.6, like that middle bowl of porridge, is just right.

—Steve Mirsky

[The above text is an exact transcript of this podcast.]

View
1. 1. VentilatorBlues 06:10 PM 12/27/10

Does that mean a bout of 'flu does us good? Whack the temp up to 105 and kill off a whole bunch of the couple of hundred of fungi that can make it at 98.6?

Reply | Report Abuse | Link to this
2. 2. georgeg23 06:15 PM 12/27/10

I heard that our average temperature is 98.2F not 98.6. I don't know if that cuts anything, but consider your argument on that basis. Does that mean a few more fungi grow in us for that? Should one soak feet in hotter water to kill off that fungus? I've noticed that minor infections on the skin can be treated with hot water.

Reply | Report Abuse | Link to this
3. 3. promytius 08:34 PM 12/27/10

I never heard anything like this before; what a remarkable observation of a not so obvious connection. I'm now wondering how many fungi are crossovers from reptiles to humans. Great stuff - thanks!

Reply | Report Abuse | Link to this
4. 4. Flyazure in reply to VentilatorBlues 08:42 PM 12/27/10

I think flu should be taken in this way: Human body temperature droped a little by some reason( like cold water in shower or not enough clothes), then it become more susceptible to fungi, then it get infected, then the body fight to get rid of the situation, one method is to rise temp to kill the fungi. So I think it means fever does us good by killing fungi. Flu is a result of low body temperature. After all if we can alway maintain a warm enough body, we don't need to suffer this disease.

Reply | Report Abuse | Link to this
5. 5. openeyes999 01:32 AM 12/28/10

Interesting. I know that animals on a "CR diet" (the only thing proven to actually slow aging in mammals, aside from the drug Rapamycin) have lower body temps in general, probably due to a slower metabolism. I haven't heard that they're more susceptible to fungus, but who knows. Anyway, all this just shows how important balance is in the body.

Reply | Report Abuse | Link to this
6. 6. Ralf123 in reply to VentilatorBlues 07:34 AM 12/28/10

Well flu might not be a good idea with all the damage a virus does but how about a sauna or high intensity exercise? Both ward off infections - systemic ones as well as those on your skin.

Reply | Report Abuse | Link to this
7. 7. abrasileirosilva 09:33 AM 12/28/10

The information below is from the link:
http://www.wolframalpha.com/ :
"Normal" body temperature of a healthy human in the US (98.6 °F)
Human | body temperature (Homo sapiens) = (35.9 to 38.1) °C (degrees Celsius) = (96.1 to 101) °F (degrees Fahrenheit)
98.6 °F (degrees Fahrenheit) = 37 °C (degrees Celsius)
98.1 °F (degrees Fahrenheit) = 36.72 °C (degrees Celsius)

Reply | Report Abuse | Link to this
8. 8. juxtapose82 11:53 AM 12/28/10

So to save the world from mass extinction due to fungus I should just put on a sweater? Awesome! I am such a savior of humanity.

Reply | Report Abuse | Link to this
9. 9. BoRon in reply to Flyazure 06:13 PM 12/28/10

Flu is caused by a virus. I don't think a cold shower or the wrong clothes will give it to you.

Reply | Report Abuse | Link to this
10. 10. krish.mallipeddi 07:33 PM 12/28/10

@juxtapose - Unfortunately, simply wearing a sweater doesnot result in your body temp increasing to over 100 F. You will probably just start sweating thereby cooling your body temp back to around 96.8.
- pharmtastic.tumblr.com

Reply | Report Abuse | Link to this
11. 11. ramanan50 in reply to VentilatorBlues 12:31 AM 12/29/10

That's a good point.Probably,Nature gives us infections to prepare ourselves to combat the other evolved organisms to maintain ecobalance,so long as we do not induce infections artificially by ourselves.

Reply | Report Abuse | Link to this
12. 12. ramanan50 12:35 AM 12/29/10

I think it is Nature's way of maintaining ecobalnce to have one infected , increase body immunity system and prepare to meet the challenge of other growing organisms.

Reply | Report Abuse | Link to this
13. 13. juxtapose82 in reply to krish.mallipeddi 10:24 AM 12/29/10

So, I'm not a hero? Dammit, back to the drawing board. But thanks for sucking the fun out of my day.

Reply | Report Abuse | Link to this

### Add a Comment

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Click one of the buttons below to register using an existing Social Account.

## More from Scientific American

• Plugged In | 10 hours ago

### What unconventional fuels tell us about the global energy system

• News | 12 hours ago

### Shooting the Wheeze: Whooping Cough Vaccine Falls Short of Previous Shot’s Protection

• Guest Blog | 13 hours ago

### Dissecting the controversy about early psychological response to disasters and trauma

• Ask the Experts | 17 hours ago | 13

### What Role Does Climate Change Play in Tornadoes?

• Reuters | 17 hours ago | 1

### The 10 Deadliest Tornadoes in U.S. History

See what we're tweeting about

More »

## Latest from SA Blog Network

• ### Fat Tuesday: Hungry for love

MIND
Illusion Chasers | 9 hours ago
• ### What unconventional fuels tell us about the global energy system

Plugged In | 10 hours ago
• ### Dissecting the controversy about early psychological response to disasters and trauma

Guest Blog | 13 hours ago
• ### Why Are Barns Red?

Image of the Week | 13 hours ago
• ### The SciArt Buzz: ScienceArt On Exhibit In May/June 2013

Symbiartic | 14 hours ago

## Science Jobs of the Week

98.6 Trades Metabolic Cost for Fungal Protection

X

### Subscribe Today

Save 66% off the cover price and get a free gift!

X

X

###### Welcome, . Do you have an existing ScientificAmerican.com account?

Yes, please link my existing account with for quick, secure access.

No, I would like to create a new account with my profile information.

X

Are you sure?

X

### Institutional Access

It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. To access this article in its entirety through site license access, click below.

X

X